This project involves efficient, economical testing of widely used herbicides to determine their mutagenic properties. The genetic assays in this screening program use Drosophila melanogaster with well-established tests for sex-linked recessive lethals, dominant lethals and chromosomal loss. The herbicides selected for testing have chemical structures which suggest a potential for mutagenic activity, these being carbamates, substituted phenols, urea compounds, triazines, and base analogs. Treatments are administered to adults by injection and to larvae by ingestion. Herbicides being tested include alachlor, atrazine, bromacil barban, butylate, ametryn, CDEC, cyanazine, cycloate, dinoseb, diuron, chlorbromuron, EPTC, GS-14254, linuron, metham, monuron, propachlor, trifluralin, and terbacil, vernolate.